path: root/lib/CodeGen/CodeGenFunction.h

//===--- CodeGenFunction.h - Per-Function state for LLVM CodeGen ----------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This is the internal per-function state used for llvm translation. 
//
//===----------------------------------------------------------------------===//

#ifndef CLANG_CODEGEN_CODEGENFUNCTION_H
#define CLANG_CODEGEN_CODEGENFUNCTION_H

#include "clang/AST/Type.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/Support/LLVMBuilder.h"
#include <vector>

namespace llvm {
  class Module;
}

namespace clang {
  class ASTContext;
  class Decl;
  class FunctionDecl;
  class ObjCMethodDecl;
  class TargetInfo;
  class FunctionTypeProto;
  
  class Stmt;
  class CompoundStmt;
  class LabelStmt;
  class GotoStmt;
  class IfStmt;
  class WhileStmt;
  class DoStmt;
  class ForStmt;
  class ReturnStmt;
  class DeclStmt;
  class CaseStmt;
  class DefaultStmt;
  class SwitchStmt;
  class AsmStmt;
  
  class Expr;
  class DeclRefExpr;
  class StringLiteral;
  class IntegerLiteral;
  class FloatingLiteral;
  class CharacterLiteral;
  class TypesCompatibleExpr;
  
  class ImplicitCastExpr;
  class CastExpr;
  class CallExpr;
  class UnaryOperator;
  class BinaryOperator;
  class CompoundAssignOperator;
  class ArraySubscriptExpr;
  class OCUVectorElementExpr;
  class ConditionalOperator;
  class ChooseExpr;
  class PreDefinedExpr;
  class ObjCStringLiteral;
  class ObjCIvarRefExpr;
  class MemberExpr;

  class BlockVarDecl;
  class EnumConstantDecl;
  class ParmVarDecl;
  class FieldDecl;
namespace CodeGen {
  class CodeGenModule;
  class CodeGenTypes;
  class CGRecordLayout;  

/// RValue - This trivial value class is used to represent the result of an
/// expression that is evaluated.  It can be one of three things: either a
/// simple LLVM SSA value, a pair of SSA values for complex numbers, or the
/// address of an aggregate value in memory.
class RValue {
  llvm::Value *V1, *V2;
  // TODO: Encode this into the low bit of pointer for more efficient
  // return-by-value.
  enum { Scalar, Complex, Aggregate } Flavor;
  
  // FIXME: Aggregate rvalues need to retain information about whether they are
  // volatile or not.
public:
  
  bool isScalar() const { return Flavor == Scalar; }
  bool isComplex() const { return Flavor == Complex; }
  bool isAggregate() const { return Flavor == Aggregate; }
  
  /// getScalar() - Return the Value* of this scalar value.
  llvm::Value *getScalarVal() const {
    assert(isScalar() && "Not a scalar!");
    return V1;
  }

  /// getComplexVal - Return the real/imag components of this complex value.
  ///
  std::pair<llvm::Value *, llvm::Value *> getComplexVal() const {
    return std::pair<llvm::Value *, llvm::Value *>(V1, V2);
  }
  
  /// getAggregateAddr() - Return the Value* of the address of the aggregate.
  llvm::Value *getAggregateAddr() const {
    assert(isAggregate() && "Not an aggregate!");
    return V1;
  }
  
  static RValue get(llvm::Value *V) {
    RValue ER;
    ER.V1 = V;
    ER.Flavor = Scalar;
    return ER;
  }
  static RValue getComplex(llvm::Value *V1, llvm::Value *V2) {
    RValue ER;
    ER.V1 = V1;
    ER.V2 = V2;
    ER.Flavor = Complex;
    return ER;
  }
  static RValue getComplex(const std::pair<llvm::Value *, llvm::Value *> &C) {
    RValue ER;
    ER.V1 = C.first;
    ER.V2 = C.second;
    ER.Flavor = Complex;
    return ER;
  }
  static RValue getAggregate(llvm::Value *V) {
    RValue ER;
    ER.V1 = V;
    ER.Flavor = Aggregate;
    return ER;
  }
};


/// LValue - This represents an lvalue references.  Because C/C++ allow
/// bitfields, this is not a simple LLVM pointer, it may be a pointer plus a
/// bitrange.
class LValue {
  // FIXME: Volatility.  Restrict?
  // alignment?
  
  enum {
    Simple,       // This is a normal l-value, use getAddress().
    VectorElt,    // This is a vector element l-value (V[i]), use getVector*
    BitField,     // This is a bitfield l-value, use getBitfield*.
    OCUVectorElt  // This is an ocu vector subset, use getOCUVectorComp
  } LVType;
  
  llvm::Value *V;
  
  union {
    llvm::Value *VectorIdx;   // Index into a vector subscript: V[i]
    unsigned VectorElts;      // Encoded OCUVector element subset: V.xyx
    struct {
      unsigned short StartBit;
      unsigned short Size;
      bool IsSigned;
    } BitfieldData;           // BitField start bit and size
  };
public:
  bool isSimple() const { return LVType == Simple; }
  bool isVectorElt() const { return LVType == VectorElt; }
  bool isBitfield() const { return LVType == BitField; }
  bool isOCUVectorElt() const { return LVType == OCUVectorElt; }
  
  // simple lvalue
  llvm::Value *getAddress() const { assert(isSimple()); return V; }
  // vector elt lvalue
  llvm::Value *getVectorAddr() const { assert(isVectorElt()); return V; }
  llvm::Value *getVectorIdx() const { assert(isVectorElt()); return VectorIdx; }
  // ocu vector elements.
  llvm::Value *getOCUVectorAddr() const { assert(isOCUVectorElt()); return V; }
  unsigned getOCUVectorElts() const {
    assert(isOCUVectorElt());
    return VectorElts;
  }
  // bitfield lvalue
  llvm::Value *getBitfieldAddr() const { assert(isBitfield()); return V; }
  unsigned short getBitfieldStartBit() const {
    assert(isBitfield());
    return BitfieldData.StartBit;
  }
  unsigned short getBitfieldSize() const {
    assert(isBitfield());
    return BitfieldData.Size;
  }
  bool isBitfieldSigned() const {
    assert(isBitfield());
    return BitfieldData.IsSigned;
  }

  static LValue MakeAddr(llvm::Value *V) {
    LValue R;
    R.LVType = Simple;
    R.V = V;
    return R;
  }
  
  static LValue MakeVectorElt(llvm::Value *Vec, llvm::Value *Idx) {
    LValue R;
    R.LVType = VectorElt;
    R.V = Vec;
    R.VectorIdx = Idx;
    return R;
  }
  
  static LValue MakeOCUVectorElt(llvm::Value *Vec, unsigned Elements) {
    LValue R;
    R.LVType = OCUVectorElt;
    R.V = Vec;
    R.VectorElts = Elements;
    return R;
  }

  static LValue MakeBitfield(llvm::Value *V, unsigned short StartBit,
                             unsigned short Size, bool IsSigned) {
    LValue R;
    R.LVType = BitField;
    R.V = V;
    R.BitfieldData.StartBit = StartBit;
    R.BitfieldData.Size = Size;
    R.BitfieldData.IsSigned = IsSigned;
    return R;
  }
};

/// CodeGenFunction - This class organizes the per-function state that is used
/// while generating LLVM code.
class CodeGenFunction {
public:
  CodeGenModule &CGM;  // Per-module state.
  TargetInfo &Target;